Web control sensing nozzle



June 19, 1962 J. M. DEERING 3,039,483

WEB CONTROL SENSING NOZZLE Filed Feb. 25, 1960 2 Sheets-Sheet 1 INVENTOR.

zfosep/z Mjeerzz June 19, 1962 J. M. DEERING 3,039,483

was CONTROL SENSING NOZZLE Filed Feb. 25, 1960 2 Sheets-Sheet 2 States Unite This invention relates to the art of web control and more particularly to a sensing nozzle for use in a web control system.

Many types of systems have been proposed and utilized for the purpose of web guiding, that is, controlling the flight of a web, or sheet of material as it moves from one roll to another. The system of the present invention is of the type wherein a pneumatic jet stream is positioned at an edge of the web, which stream is normal to the surface of the web, and is arranged to be interrupted by lateral movement of the web, thus generating a signal which is transmitted to apparatus adapted to realign the flight of the web within predetermied tolerances. More specifically, the system of the present invention utilizes pneumatic slotted edge-sensing nozzles capable of maintaining the longitudinal centerline of a moving web within a given path, even though the web width varies as much as :3 to 4" per edge.

While prior art web control systems may have utilized slotted nozzles, difliculties were experienced with such nozzles because of non-uniform flow pressure conditions in the nozzle jet stream, caused primarily by air flow turbulence within the nozzle cavity. The nozzle of the present invention, due to its unique structure and manner of handling internal air flow, avoids the shortcomings of slotted edge-sensing nozzles of the prior art, and operates to provide uniform pressure in the nozzle jet stream, thus making practical, centerline control of webs having as much as :3" to 4 variation per edge.

The main object of this invention is to provide a web control system for maintaining the centerline of a moving web within a predetermined path.

A more specific object is to provide a web control system for maintaining the centerline of a moving web within a predetermined path even though the width of the web varies an appreciable amount.

Still another object of the invention is to provide slotted nozzles for use in a web control system, which nozzles develop uniform pressure in the nozzle jet stream so that practical centerline control of moving webs can be had even when the web width varies 13 to 4" per edge.

These and further objects and features of the subject invention will become more apparent from the following description and accompanying drawings wherein:

FIG. 1 is a schematic view illustrating a web control system embodying the principles of the invention;

FIG. 2 is an elevation view of a nozzle assembly used in the web control system illustrated in FIG. 1

FIG. 3 is a view generally as seen from line 33 in H6. 2; and

FIG. 4 is a view similar to that of FIG. 3, but with a nozzle plate removed.

Referring now to the drawings, and more particularly to FlG. 1, the numeral identifies a web, or sheet of material being unwound from an inventory roll 12 and moving in a path including passage beneath a first idler roll 14 and above a second idler roll 16, and onward to one or more rolls (not shown) as required in some type of operation, or processing as the case may be. While the web 10 is shown as being unwound from the roll 12, it may be desired to reverse web travel in a given operation, that is, to wind the web on the roll 12. In either direction of web travel, the important objective is to maintain the longitudinal centerline of the web in a prede- 3,039,433 Patented June 19, 1962 tel-mined path, such as a straight line. The purpose of the web control system of the invention is to accomplish this objective, and toward this end includes a pair of web edge sensing nozzle assemblies 18, 20, a hydraulic controller 22, and a roll position control assembly 24.

The nozzle assemblies 18, 20, which are identical in structure but different in location relative to the web 10, are formed to provide a C-shaped or yoke-line configuration between the jaws of which the web 10 is arranged to travel, said nozzle assemblies each being oppositely disposed along the respective edges of the web. A supply of pressure fluid, such as compressed air, is fed to the nozzle assemblies 18, 20 by way of a supply pipe 26 and connecting branch pipes 28, 30, each of the latter having a standard type air filter 32 and a pressure regulator 34, as shown.

The purpose of the sensing nozzles 18, 20, is to develop a pressure signal indicative of the lateral position of the moving web 10 as it travels past the nozzles, which signal is transmitted to the controller 22. Variation of the pressure signal from a predetermined norm, caused by shift in lateral position of the web, initiates controller operation whereby the roll position control assembly 24 is activated to cause readjustment of lateral position of the moving web, so that the web will travel in the desired path. As long as the web is traveling in a predetermined path, for example, the centerline running straight, the pressure signal will remain at the norm and no corrective action of the control assembly 24 will be initiated.

Each nozzle assembly 18, 20, as best seen in FIGS. 2-4,

includes a lower jaw, or nozzle block 36, an upper jaw,

or nozzle block 38, and a support block 40 to which the nozzle blocks are affixed in parallel spaced relation by means, such as screws 42. An elongated, or slot-like cavity 44 is formed in the lower block 36, while longi-' tudinally extending passageways 46 are provided at each end of the cavity as shown for receiving the ends of conduit, or piping 48, which lead from supply branch pipes 28 or 30. Attention is directed to the fact that the configuration and length of piping 48, extending in branch fashion from supply pipes 28 or 30, is similar, viz. distances A=A. A recess 50 formed in the top surface of nozzle block 36 is arranged to receive a nozzle plate 52, which is held in positon by fastening means such as screws 54. The plate 52 has a long, narrow slot 56 adapted to coincide with the longitudinal center line of cavity 44 when the plate is secured in position on the block 36. The upper nozzle block 38 is similar in construction to block 36, and includes an elongated, or slot-like cavity 58, with a longitudinally extending passageway 60 at one end for receiving the end of a conduit, or pipe 62 or 64, leading to the controller 22, as well as a nozzle plate 64 secured by screws 54- within a recess 66 formed in the surface of the block 38. The nozzle plate 64 has a long, narrow slot 68 which, is arranged to lie within the same vertical plane as that of nozzle plate slot 56. In view of such construction, a curtain, or sheet of pressurized air will be maintained in the jaws of the yoke provided by the parallel arranged nozzle blocks 36, 38, when compressed air is fed into the lower block 36 via conduit 48.

The degree of recovery pressure caused by passage of said curtain into the upper block 38 by way of the slot 64, will be determined primarily by the amount by which the edge of the web of material 10 intercepts said curtain as it moves through the jaws of the nozzle. Change in lateral movement of the web of material, causes change of recovery pressure, thus generating a pressure signal which is transmitted to the controller 22. An extension or arm 70 of the support block 40 is provided for securing the nozzle assembly in fixed position at the edge of the web of material, by holding means (not shown).

It is important to note that the symmetrical arrangement of the conduit 48 as it conducts pressurized air into the nozzle block 36 in a straight and smooth manner, results, in development of a jet stream within the jaws of the nozzle assembly yoke, that is of uniform pressure throughout the length of the jet stream. This results in production of a pressure signal within the upper nozzle block 38, that is dependent primarily upon actual jet stream recovery, hence, providing a pressure signal that bears an accurate relationship to the degree in which the edge of the Web intercepts the jet stream. When such pressure signal is transmitted to the controller 22, the latter functions to control the lateral position of the web of material in a manner which will now be described.

Controller 22 includes a jet pipe 72 pivotably mounted at one end and adapted for receipt of hydraulic fluid for ejection in a jet stream at the other end, a jet stream receiver including receiver orifices and associated passageways 74, 76, a distributing cylinder '78 having a valving piston 80 slidably arranged therein, a pressure differential unit in the form of a diaphragm assembly 82 including a diaphragm 84 which is arranged to cause movement of the jet pipe 72 by means of a rod 86, a setpoint means in the form of an adjustable coil spring 88, a source of pressurized hydraulic fluid including a pump 94 a pump driving motor 92, and a reservoir 94, and a solenoid operated valve 96.

When the controller 22 is in operation, the valve 96 will direct hydraulic pressure fluid from the pump 9% to the distributing cylinder 78 so that the valving piston Si is moved to the position shown (FIG. 1). In such position, an open hydraulic fluid flow path will be provided from the passageways 74,76, through the cylinder 78, and into either conduits, or pipes 98, N leading to opposite ends of a cylinder 162 forming part of the roll position control assembly 24. A piston 104, slidably arranged within the cylinder 162, is responsive to a pressure differential caused by unequal fluid pressure on either side thereof by reason of fluid flow from pipes 98 and 100, to cause lateral movement of the inventory roll 12. The signal pressure pipes 62 and 64 lead to chambers in the diaphragm assembly 82 on opposite sides of diaphragm 84. A compression spring 106, is arranged in the distributing cylinder 78, to cause movement of the valving piston 80 so that the ends of receiver passages 74 and 76 are blocked when the controller is not in operation. For such purposes, the solenoid of the valve 96 and the motor 92, may be tied in to the same electrical circuit.

From the foregoing it will be seen that the system of the invention will automatically operate. to maintain the flight of the web 10 in a predetermined path. Assume that it is desired to maintain the centerline of the web equidistant between the nozzle assemblies 18, 20. In such position of the web, the edges thereof will intercept like portions of the nozzle jet curtain, thus generating equal pressure signals for transmission to the diaphragm assembly 82. If the angular position of the jet pipe 72 has been adjusted so that the free end thereof is equidistant from the orifices of passageway 74, 76, under such equal pressure signals, it will be seen that hydraulic flow through the cylinder 78 will be equally divided, so that hydraulic pressure transmittal to roll position control assembly 24 will be balanced, i.e., no pressure differential will exist on piston 104, and the inventory roll 12 Will remain in fixed lateral position.

Assume now that the web 10 begins to drift, or move laterally toward nozzle assembly and away from nozzle assembly 18. The recovery pressure in nozzle assembly 26 will decrease while that in nozzle assembly 18 will increase, thus generating differing pressure signal transmission to diaphragm assembly 82. As a result, the diaphragm 84 will experience a pressure differential causing bulging or movement to the right, thus allowing spring 88 to rotate the jet pipe 72 in a clockwise direction. In such new position of the jet pipe, liquid pressure in pipe will decrease while pressure in pipe 93 will increase thus creating a pressure differential upon control assembly piston iii-4 so that the latter will move toward the right, and cause movement of the inventory roll 12 toward the right. Movement of the roll to the right will laterally reposition the web 10 so that it will move toward nozzle assembly 18 and away from nozzle assembly 29. Such lateral movement of web 10 will continue until the edges thereof intercept equal amounts of the respective nozzle jet sheets, whereupon the recovery pressure will again transmit equal pressure signals to the diaphragm assembly 82, resulting in counter-clockwise movement of jet pipe 72 until the free end thereof is equidistant from the orifices of receiver passageways 74, 76, at which point the system will again be in equilibrium.

Should the Web 10 move laterally toward the nozzle assembly 18 and away from nozzle assembly 29, it will be seen that the system of the invention will automatically operate to cause corrective lateral movement of the web back toward initial, or predetermined position. In such manner, the system of the invention quickly takes corrective action to assure web travel in a predetermined path. By making the nozzle slot of great length, large variation in web width may be handled. For example, a nozzle slot length of between 6 to 8 inches, provided accurate web alignment control when the web width varied between 3 to 4 inches per edge. Without the unique structural features and arrangement of the nozzle of the invention, such excessive web width variation would make accurate web control difficult, if not impossible.

The foregoing description has been given in detail without thought of limitation since the inventive principles involved are capable of assuming other forms without departing from the spirit of the invention or the scope of the following claims.

What is claimed is:

l. A web edge sensing nozzle generally of C shape having a pressure jaw and a recovery jaw, each of said jaws being formed to provide an elongated cavity having a length at least twice its greatest cross-sectional dimension, and first and second conduits connected individually to opposite ends of the elongated cavity of said pressure jaw to supply pressurized medium to both ends of said cavity of said pressure jaw, thereby to provide a flow of said medium from said pressure jaw to said recovery jaw in a sheet having a pressure which is substantially uniform in the direction of said elongated cavities.

2. A web edge sensing nozzle having a yoke-like configuration with a pressure jaw and a recovery jaw arranged in the same vertical plane, each of said jaws being formed to provide an elongated cavity with an elongated slot, and first and second separate conduits connected to opposite ends of the slot of said pressure jaw and to a common pressure source for supplying pressurized medium to both ends of the cavity of said pressure jaw.

3. A web edge sensing nozzle having a yoke-like configuration with a low-er and an upper jaw, each of said jaws being formed to provide an elongated cavity, each jaw having a nozzle plate arranged to enclose the cavity, each nozzle plate being formed to provide an elongated slot having a length at least ten times its width, said slots being arranged to lie in the same plane, and means to supply pressurized medium to both ends of the cavity of one of the jaws.

4. A web edge sensing nozzle having a yoke-line configuration with a lower and an upper jaw, each of said jaws being formed to provide an elongated cavity, each jaw having a nozzle plate arranged to enclose the cavity, each nozzle plate being formed to provide an elongated slot, said slots being arranged to lie in the same vertical plane, first and second separate conduits connected to opposite ends of the cavity of one of the jaws to supply pressurized medium to both ends of said cavity, and

means to allow egress of recovered medium from the cavity of the other jaw.

5. A web edge sensing nozzle having a C-shaped configuration with a pressure jaw and a recovery jaw, each of said jaws being formed to provide an elongated cavity having a length at least twice as great as its greatest crosssectional dimension, each jaw having a nozzle plate arranged to enclose the cavity thereof, each nozzle plate being formed to provide an elongated slot, said slots each having lengths at least ten times as great as their widths and being arranged to face each other, first and second conduits connected to opposite ends of the cavity of said pressure jaw to simultaneously supply equal quantities of pressurized medium and at equal rates to both ends of said cavity of said pressure jaw, and a recovery conduit connected to said recovery jaw to provide egress of recovery medium from the cavity of said recovery jaw.

6. A web edge sensing nozzle having a C-shaped configuration with a lower and an upper jaw, each of said jaws being formed to provide an elongated cavity, each jaw having a nozzle plate arranged to enclose the cavity thereof, each nozzle plate being formed to provide an elongated slot, said slots being arranged to lie in the same vertical plane, separate first and second conduit means arranged at opposite ends of the cavity of one of the jaws to direct a flow of pressure medium into the cavity and in the direction of the longitudinal centerline thereof, said conduit means being symmetrically arranged and jointly served by a common pressure fluid supply line, and a conduit means for egress of recovered medium from the cavity of the other jaw.

References Cited in the file of this patent UNITED STATES PATENTS 2,779,549 Teplitz Ian. 29, 1957 2,808,067 Ziebolz Oct. 1, 1957 2,813,535 Markey Nov. 19, 1957 2,941,572 Densen et al June 21, 1960 FOREIGN PATENTS 201,182 Australia Jan. 17, 1957 

